RAID volumes employ two or more disk drives, which act in combination as one large disk drive, for improved fault tolerance and performance. Businesses often implement RAID volumes because some such volumes can remain functional if one or more of the disk drives fails or becomes damaged. This can be invaluable to businesses by preventing downtime and/or loss of valuable data when a disk drive becomes damaged. When setting up a RAID volume, it is desirable to calculate space used on each disk drive (i.e., capacity) so that maximum compatibility with disk drives from various vendors and having various sizes is maintained. This ensures that a user is not restricted to a specific disk drive model, size or vendor if the user needs to replace a disk drive used in his or her existing RAID configuration. This method of disk drive sizing is often referred to as disk drive coercion.
The process of determining the optimal disk drive usage size has become increasingly difficult given the increasing size of disk drives and resulting larger margin for size variance in disk drives from multiple vendors labeled as having the same capacity. One of the most difficult situations involves the interpretation of what the size of a “Gigabyte” (GB) is. Some vendors use this measurement to refer to 2^30 bits, while others use it to refer to 10^9 bits. Consequently, 2 disk drives from different vendors may both be listed as having the same capacity in Gigabytes, but vary drastically in actual capacity. Current examples of disk coercion, such as predefined table lookup methods or rounding down methods (to the nearest 1 GB, nearest 512 MB boundary, etc.) do not adequately address the above-referenced problems in that they: 1) fail to provide a large range of usable disk drive sizes; and 2.) fail to adequately account for disk drives sized using different interpretations of what a Gigabyte is.
Therefore, it would be advantageous to devise a system and method to coerce the size used on a disk drive in a RAID volume such that disks listed with the same size in Gigabytes, that have different actual sizes due to different interpretations of what a Gigabyte is, would be interchangeable for use in a RAID configuration.